The storage of data and the retrieval of the data in/from electronic memories are sometimes subject to errors linked to writing, reading and sometimes to the electronic memories themselves.
These errors, which bring about losses from the stored data, can have not insignificant consequences. Moreover, it is important to be able to detect the fault in the storage means as rapidly as possible when said storage means degrades, so as to take suitable measures.
This is particularly the case when the data are data associated with the operation of an aircraft and the quantity of which increases continually.
The French patent application published under the number FR3001818 discloses a device for duplicating data on different storage devices.
In aeronautics, standards are provided that qualify the quality assurance level of equipment.
The quality assurance level or DAL, for “Design Assurance Level”, of a piece of avionic equipment defines the demands relating to the level thereof.
The levels of DAL are defined in the Eurocae document ED-79/SAE ARP 4754A, for example. This document defines five quality levels from DAL-A to DAL-E in decreasing order of quality assurance. The level DAL-A corresponds to the highest quality level and the level DAL-E corresponds to the lowest quality level. DAL-A level equipment is used for avionic functions that are critical for the aircraft, whereas DAL-E level equipment is used for functions that have no impact on the safety of the aircraft.
The high quality levels often make it impossible to use high-capacity modern storage means. These storage means quite often have onboard controllers and software that are difficult to access and difficult to qualify in terms of quality.